Automatic shutoff nozzles, such as those used in gasoline filling stations, conventionally have a main liquid flow conduit for delivering liquid through the nozzle so that it may be expelled from the spout of the nozzle and into a receiving container, such as a gas tank in a vehicle. Such automatic shutoff nozzles typically use the reduced pressure created by an inline Venturi, to automatically shut off the flow of fluid passing through the main liquid flow conduit when the receiving container becomes full. This detection of liquid occurs when the receiving container becomes nearly full.
The flow of liquid through such automatic shutoff nozzles passes through a Venturi, which creates a reduced pressure and in turn generates a flow of air and vapor within the nozzle. The flow of air and vapor created by the Venturi is plumbed so as to be drawn from the tip of the nozzles spout and is introduced into the flow of liquid, which is exiting the nozzle.
The flow of liquid through these Venturi style nozzles is caused to automatically terminate when the fluid levels in the receiving container rise to cover the vapor inlet at the tip of the spout of the nozzle. This automatic termination occurs because the viscosity of the liquid is greater than the viscosity air. The liquid covering the tip will not flow readily into the air inlet of the spout, and this lag will cause the pressure within the airway to the Venturi to decrease.
The decrease in pressure will cause the nozzle to “click off” because in addition to the airway of the Venturi being plumbed to the tip of the spout, the airway is also plumbed to a diaphragm connected to a linkage system that interconnects the hand actuated trigger and the nozzle's liquid control valve. The decrease in pressure within the airway of the Venturi will cause the diaphragm to actuate mechanisms that cause the linkage system to disengage the trigger from the valve, thus allowing the valve to close and terminate the flow of liquid through the nozzle.
One such system is disclosed in U.S. Pat. No. 5,474,115 issued Dec. 12, 1995, to Fink, Jr. and entitled Specialty Fuel Dispensing Nozzle. The main valve (a poppet valve) is opened by the operating lever, the rush of fuel through the nozzle body unseats a check valve so fuel can flow through the Venturi to the nozzle spout and outlet. The Venturi is installed in a circular housing which defines the outlet. There is a shutoff assembly that is controlled, in part, by a diaphragm assembly. A chamber is defined above the diaphragm assembly which is connected to the Venturi by an air passage. When fuel flows over the Venturi, a partial vacuum is created that is communicated to the chamber via the air passage.
The fuel dispensing nozzle has a vent tube extending through a spout of the nozzle and automatic shut off device in communication with, and responsive to, the passage of air through the vent tube. The outer end of the vent tube terminates in an air port at the tip of the spout. A tip, forming a valve, is placed at the outer end of the vent tube. The valve has a magnetic responsive valve member and a seat formed at the junction of tip and the vent tube. The vacuum created by the nozzle seats the magnetic valve member against the seat to close the tube.
The vent tube is operatively connected at its opposite other end to an air passage that is in fluid communication with the Venturi. During fuel flow, the Venturi creates a vacuum that draws air through the vent tube from its outer end to its inner end. This flow of air prevents a vacuum from occurring in the chamber, thus preventing the operation of the automatic shut-off. When the outer end of the vent tube is blocked by fuel, a vacuum is created in the vent tube. Accordingly, the vacuum created by the Venturi causes a corresponding vacuum in the chamber via the air passage, thus allowing the operation of the automatic shut-off.
It is the object of this invention to provide an auto-shutoff nozzle, which utilizes the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full.
It is the object of this invention to provide an auto-shutoff nozzle, which utilizes the reduced air pressure of the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full.
It is the object of this invention to provide an auto-shutoff nozzle, which is usable in a portable fuel transfer system, and which is responsive to conditions of the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full.
It is the object of this invention to provide an auto-shutoff nozzle, which nozzle is usable in a gasoline filling station, and which is responsive to conditions of the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full.
It is the object of this invention to provide an auto-shutoff nozzle with a removable spout, which is responsive to conditions of the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full.
It is the object of this invention to provide an auto-shutoff nozzle, which is responsive to conditions of the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full, and wherein the spout is an auto-closure spout.
It is the object of this invention to provide an auto-shutoff nozzle, which is responsive to conditions of the airflow within the vapor recovery means of the nozzle to cause the nozzle to automatically shut off when the receiving container is nearly full, and wherein the nozzle is usable in a liquid delivery system having vapor recovery.